Preparation of drying oils



or "weakly basic reacting salts.

Patented June 3, 1952 PREPARATION OF DRYING OILS Howard Teeter, Peoria,;- 111., assignor l-to the United States of America as-represented bythe Secretary 'of Agriculture -No DrawingJ- Application August 151950, I" Serial No. 178,162

(Granted under the act of March-'3; "1883, as amended April 30, 1928; 870 0. G. 757) 11 Claims.

The invention herein described may be manu factured and used by or for the Government of the United States of America for governmental purposes throughout the world without the payment to me of any royalty thereon.

This invention relatesin general to the conversion ofnon-drying oils to drying oils or more 5 broadly, to the treatment of esters "of aliphatic --acicls containing at least 8 carbon atoms in the 'acyl radical to increase the olefinic unsaturation thereof, particularly the conjugated unsatura- ',tion. In the case of semi-drying oils or nondrying oils the drying properties of said oils are fmaterially enhanced. The invention relates, in particular, to an improved method for removing the halogen substituents of a halogenated glyceride oil whereby the olefinic unsaturation of said oil is increased. Among'the known methods for treating glyceride oils to improve the: drying properties thereof, it is conventional procedure to first "halogenate and then'rem'ove'the halogen to ef- "fect unsaturation. In the past, various methods have been suggested for both the halogenation and halogen-removing steps. The present invention relates to the second, halogen-removing 'step,' and generally involves treating a halogencontaining glyceride oil with aqueous solutions I have discovcred that my novel method of halogen removal produces an oil with markedly improved dry- 'i'ng properties. The invention is remarkably "simple and easy to'carry'out, at the same time 'being relatively low in cost. 1

"Prim-methods of halogen removing, particularly dehydrohalogenation of long chain fatty acid compounds, such as esters, and, more particularly, esters of polyhydric alcohols, such as glycerol, have involved thermal treatment by which 'h'ydrohalic acids are evolved; or treat- "m'entwith relatively strong bases, such as aqueoussolutions of caustic soda, alkali metal carbonates and the like.' The evolution of hydro- "genfhalides is decidedl disadvantageous from the-standpoint of equipment corrosion and general inconvenience. Treatment with strong bases,"on the other hand, requires considerable .caution to prevent excessive hydrolysis of the fat acid esters. I The 'reaction between certain halogen-containing organic compounds and aqueous solutions of salts of weak acids has heretofore resulted'i'n substitution of the halogen group by a hydroxyl'g'roupl' The chemical phenomenonof substitution is of no benefit inimproving "the drying properties of long chain fatty acid compounds, and it normally requires a further step of dehydration in order .to introduce unsaturated linkages in the long chain aliphatic radicals.

I have discovered .that aqueous solutions of certain salts of weak acids are capable of effecting dehydrohalogenation of halogen-containing esters oithe type previously mentioned. My results indicate that a certain amount of halogen substitutionby hydroxy groups takes place concurrently with dehydrohalogenation, but have discovered the furtherremarkable fact that this phenomenonof substitutionappears actually to .increase the valuable drying'properties of my treatedcompounds.

'I employ aqueous'solutionsof salts of acids having'an'ionization constanuor 2 10- or less.

The acids may "b'e' organie carboxylic "acids or inorganic 'oxygen co'ntaining acids; *and examples' of suitable salts are alkali metal 1 acetates,

--borates, acid phosphates, propionates',-' maleates, valerates, acid; pyrophosphates; *malonates, -bicarbonates, soaps of aliphatic long chain-acids and the like. Salts other tha'n alkali-metal salts may likewise be'used, such as" ammonium or amine salts, 'cupric, ferric; barium, calcium, magnesium, etc. "Alkali metal salts are'preferred, however. I v V The halogen containing esters s'uitable'in-imy process may be any longchain*ali-phatieacid esters, although my invention is-particula rly dir'ected to "esters of aliphatic polyhydric -alcohols.

Inasmuch as the specific method *of halogenation appears to "produce characteristic"-typesFof halogen containing compounds," I have determined by experimentation that any'suchcompound may be employed so long, as the contained halogen. does not existon adjacent carbon atoms in the aliphaticchain. I have 'discoveredghowever, that halogenated unsaturated glyce'rides produced by halogenating glyceride. oils with certain positive halogen compounds, asdisclosed in application Ser. No. 721 830, filed Januaryl3, 1947, by "Teeter and Cfowan; now Patentz'No.

2,557,159, are especiallyzadaptable'tojmy process.

In general, according to' that invention; the

unsaturated higher fatty acid or 7 its derivative is reacted under substantially anhydrous conditions with the alkyl h'ypohalite at a suitable temperature of about from 30 to C. A'solvent, such as carbon tetrachloride, benzene, "chloroform, or petroleum ether may be employed, if desired. Reaction occursrapidly and is complete in about from one to sixty, minutes depfen'ding upon the temperature and the reactivity of the particular alkyl hypohalite employed.

The following example illustrates the halogenation method in accordance .with said pending application. "It will' be understood, however, that halogenated .esters prepared by other methods of halogenation are operative in the process so long as the halogen'does not exist on adjacent carbon atoms in the aliphatic chain.

In a 500 ml., B-necked flask equipped with thermometer, stirrer, and'reflux condenser and kept in a constant-temperature bath at about 60 C., was placed 250 g. of alkali-refined soybean oil. By means of a dropping funnel having a long outlet tube extending through thereflux condenser to a point below the surface of the oil, 92 g. of tertiary butyl hypochlorite was added dropwise; An induction period of about experiments. The reaction conditions are specified in the table, and it is to be noted that in all cases the unsaturation, particularly conjugated unsaturation is considerably increased. The original oils, before halogenation and subsequent treatment by the process of my invention, contained negligible conjugated unsaturation. All dechlorinated oils possessed drying properties equal to or superior to refined linseed oil. Example 1 was a soybean oil control chlorinated with tertiary butyl hypochlorite by the process of the copending patent application previously referred to. Example 2 was a sample of methyl oleate chlorinated in the same manner. The remainder of the examples were chlorinated soybean oil, also halogenated by the process previously referred to, all possessing halogen on non-adjacent carbon atoms of the acyl chains.

Table I Chlorine Per- Total Ex. Time Temp. Press Rea em mm- Gardner Gardner Percent Conjuga- No. (Min.) 7 00.) (p. s. 1 g Color Viscosity Hydroxyl tion Before After Percent 1. 8. 96 J 20.9 2 60 8%NaHCO3 9. 83 l. 60 3 '60 15%NaHCO; 10. 22 4. 17 1.3 28.7 4 60 15%NaHC 0 10 22 l. 43 31. 5 5 30 H 1.60 V l 1. 2 32.9 6-.. 30 1. 11 17-18 D 0. 0 25. 0 7 30 1.08 13 E I 1.0 25.3 8"-.- 30 0. 99 18 E 0. 8 16. 0 9.. 100 0. 67 17 E 1. 2 '31. 5 10 85 2. 34 14 M V 2. 0 28. 9 87 2. 72 14 J 1.6 29. 8 12 84 2. 01 15 T 1. 4 22. 9 l3 76 0. 94 15 R 2. 3 24. 2 60 Dry NaOOCCIh.-. 9.10 3.07 18 7 W 0.7 27.8 15 90 13.6%NazHPO 8. 90 2. 62 18 .T l. 2 33. 9

2'0 40 minutes, which terminated in a vigorous exothermic reaction, occurred upon initial addi tion of the hypochlorite. Following this period,

the hypochlorite was added more rapidly. After all hypochlorite had been added, the reaction mixture was stirred at about 60 C. for about 60 minutes, in order to insure complete reaction. The reaction mixture was then stripped of .vola:

" tile material by evacuating the flask at'room temperature and'pass'ing an inert gas through the mixture for approximately two hours. The product contained 9.92 percent chlorine, and its viscosity and color, determined by Gardner.

standards, were HI and 12-13, respectively;

The product was further characterized by the presence of14.6 percent diene, 5.1 percent triene,

and 1.0 percent tetraene conjugation, deter mined spectrophotometrically. The totalconjugation was 20.7 percent.

The following specific exemplary data illustr'ate my invention. It is to be understood that the specific conditions and reagents are not to bebonsideredlimiting'. For example, the time of treatment-may vary from minutes up to several hours and thetemperature of treatment may vary'from 150 C. to 250 C. and higher.

I prefer. to employ autogenous pressure, but the process may be carried out at reflux temperatures or under excess pressure up to 500 pounds p; s. i.. The concentration of the salt solution may vary over a wide range, for example, from 2 /2 percent'up to the point of saturation. I i

15 percent.

'Tabulated below are the results of a seriesof The chlorinated soybean oil used in the examples tabulated above may be replaced by chlorinated cottonseed oil, chlorinated rapeseet oil, chlorinated oiticica oil,.-chlorinated saillow'er Oil or chlorinated linseed oil. The chlorinated methyl oleate may be replaced by chlorinated ethyl lineoleate, chlorinated decyl oleate, or chlorinated oleic acid or linoleic acid.

I claim:

l. The method which comprises subjecting an ester of an aliphatic acid containing at least 8 carbon atoms in the acyl radical, said acid containing halogen substituted in the acyl radical and said substitution of halogen being upon nonadjacent carbon atoms, to the action of one of the group consisting of salts of organic carboxylic acids and salts of inorganic oxygen-containing acids, the acids of said' salts possessing an ionization constant of less than 2X 10- i 2. The method which comprises subjecting soybean oil, said oil containing halogen vsubstituted in the acyl radical of the glyceride molecule and said substitution of halogen being upon non-adjacent carbon atoms, to the action of a 5-20 percent aqueous solution of one of the group consisting of salts of organic carboxylic acids and salts of inorganic. oxygen-containing acids, the acids of said saltspossessing an ionization constant of less-than 10- 7 3. Method of -claim 2 in which the sale is sodium acid phosphate. V V

4. The method of increasin the conjugated olefinic unsaturation of a halogen containing glyceride oil, said halogen being substituted in non-adjacent relationship upon the acyl radical, comprising subjecting said halogen containing glyceride oil to the action of anaqueous solution of a weaklybasic salt of an acid possessing an ionization constant of less than 2X10- taken from the group consisting 01' organic carboxylic acids and inorganic oxygen-containing acids at a temperature in the range 150 C. to 250 C.

5. The method of increasing the conjugated olefinic unsaturation of a halogen containing soybean oil, said halogen being substituted in non-adjacent relationship upon the acyl radical of the glyceride molecule of the oil, comprising subjecting said oil to the dehalogenating action of an aqueous solution of a weakly basic salt of an acid possessing an ionization constant less than 2 10- taken from the group consisting of organic carboxylic acids and inorganic oxygencontaining acids.

6. Method of claim 5 in which the salt is sodium acetate.

7. Method of claim 5 in which the salt is sodium borate.

8. Method of claim 5 in which the salt is sodium acid phosphate.

9. The method which comprises increasing the conjugated olefinic unsaturation of chlorinated soybean oil, the chlorine being substituted in non-adjacent relationship upon the acyl radical of the oil glyceride, comprising subjecting said oil to the dechlorinating action of a 5 to 20 percent aqueous solution of a salt of the group consisting of NaHCOa, NaOOCHs, NQZBiO'I, and NazHPOe.

10. The method of claim 9 in which the salt is sodium bicarbonate.

11. The'method of claim 4 in which the halogen is chlorine.

HOWARD M. TEETER.

No references, cited. 

1. THE METHOD WHICH COMPRISES SUBJECTING AN ESTER OF AN ALIPHATIC ACID CONTAINING AT LEAST 8 CARBON ATOMS IN THE ACYL RADICAL, SAID ACID CONTAINING HALOGEN SUBSTITUTED IN THE ACYL RADICAL AND SAID SUBSTITUTION OF HALOGEN BEING UPON NONADJACENT CARBON ATOMS, TO THE ACTION OF ONE OF THE GROUP CONSISTING OF SALTS OF ORGANIC CARBOXYLIC ACIDS AND SALTS OF INORGANIC OXYGEN-CONTAINING ACIDS, THE ACIDS OF SAID SALTS POSSESSING AN IONIZATION CONSTANT OF LESS THAN 2X10-5. 